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83 grand prix no start
08-03-2014, 02:24 PM
Post: #1
83 grand prix no start
1983 grand prix ran fine yesterday now will not start today. not getting fuel into 4 barrel carb. replaced fuel filter and checked to make sure mechcanical fuel pump was working. will try to start if carb is primed with gas. any ideas? Thanks
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08-03-2014, 02:57 PM
Post: #2
RE: 83 grand prix no start
If you remove the air cleaner and look down the carb while working the throttle (choke held open) can you see gas squirting from the accelerator pump? If not then it's time to look at how much fuel is in the tank or possibly replacing that fuel pump. When you do the pump I would suggest replacing any rubber hoses too, just due to age.

Let us know what you find as it may help someone else reading these posts.
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08-03-2014, 07:45 PM (This post was last modified: 08-04-2014 12:36 AM by Garner.)
Post: #3
RE: 83 grand prix no start
NO gas seems to be pumping into carb. i am getting a number 54 fault code which is mixture control solenoid or circuit. so i dont know if its the solenoid or the ecm. any thoughts. can i check to see if theres voltage getting to the solenid?
Also there is half a tank of gas in tank and i took the fuel line off the carb and cranked the motor and plenty of fuel coming through the line.
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08-03-2014, 08:39 PM (This post was last modified: 08-03-2014 08:40 PM by Rupe.)
Post: #4
RE: 83 grand prix no start
It's been over 30 years since that carb was new and probably 20 years since I fooled with one so pardon me if I'm a little rusty.

Things to look for would be when the key is first turned on the mix sol should click (quick double click?) The mix sol is dead center in the float area of the carb and you need to remove the carb top to gain access. Both the 2 and 4 bbl versions were prone to dirt / sediment in the bowl which is very fine and can get through the filter. The other thing is the rubber o-rings in the carb don't like ethenol fuel, which is everywhere these days. That said, I doubt a bad (clogged?) mix sol will keep it from starting but if the carb bowl is empty then you know the filter is also clogged or the float / seat is not letting fuel in.... or the fuel pump is just too weak. Using a fuel pressure gauge directly on the end of the fuel line at the carb you should have at least 3 psi while cranking. If the car has a return line down at the pump the pressure will go away in a matter of seconds when you stop cranking, otherwise it should hang in that 3-4 psi range for a short bit.

If you want to check the power at the mix sol I believe it's around 5 volts but it will only be there for a second unless the engine starts. Once started the voltage will pulse so you may not be able to make it out unless you have a "noid light" or possibly an old fashion test light with a 6 volt bulb.

Chances are the sol is not open or shorted. I don't recall ever replacing one. However, they do clog and get stuck with gum / varnish just like anything else in the carb. The thing also sits in a small bore at the bottom of the bowl and that area will fill up with crud. This is where it will pay to check for pinched wires and blown fuses before you take things too far.

BTW, if you find sediment in the carb bowl that can clog the passages for the accelerator pump, which may also be worn from age or the newer fuel. IOW, you find the bowl is full but nothing squirts when you hit the throttle = dirt and wear!
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08-03-2014, 11:23 PM (This post was last modified: 08-04-2014 12:33 AM by Garner.)
Post: #5
RE: 83 grand prix no start
thanks for your help. i will keep you updated.
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08-03-2014, 11:54 PM
Post: #6
RE: 83 grand prix no start
Just a suggestion... if you scroll down the page you can use the message box instead of the reply button. That allows a post without quoting everything and at the bottom of each message you can use the edit button to add things you forgot without quoting everything prior.
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08-05-2014, 06:42 PM (This post was last modified: 08-05-2014 06:45 PM by tinman56.)
Post: #7
RE: 83 grand prix no start
got the car to start, cleared the codes then the 54 code came back for mixture control solenoid. car idles a little rough but when driving when i accelerate theres no power at all, like im not even pushing the gas pedal and some backfire ??
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08-05-2014, 10:57 PM (This post was last modified: 08-05-2014 10:59 PM by Rupe.)
Post: #8
RE: 83 grand prix no start
Yeah, as I recall that's pretty normal when the mix solenoid goes on the fritz or the power valve gets cloged on the carbs prior to the electronic versions. I can't remember in particular for that year but some of those 4 bbl carbs also had a vacuum operated secondary so if that doesn't work the other half of the carb will not open during full throttle. Basically it sounds like you either need to clean that carb or clean it and refresh some of the parts.

One thing I do recall is the early 80's vintage small V-8s didn't have a lot of power. I owned an 81 Olds Cutlass with that same carb and I played with it no end to see if I could squeeze a bit more out of it, but the computer kept the timing in check along with the mixture no matter what I did. I tell you, that was a serious learning curve and I could do one of those carbs in my sleep back then!

Bottim line is you will probably have to hunt down a carb kit, and some GOOD carb cleaner. I prefer Cyclo brand in the red / white can. It's one of the few that haven't changed formula in the last 30 years and still gets the crud out. (although a bit rough on the hands) While you have it apart find a choke pull off and a vacuum secondary diaphram. You can check the mix sol with a meter if it's not open or shorted then all you have to do is clean it till you can hear it rattle when you give it a good shake. The carb kit will have the necessary o-rings to make it seal properly when installed. Figure spending $50 - $100 if you can tackle the project yourself. If you opt to buy a rebuilt unit they are probably near $350 these days. (discounted price) That carb is the "better mouse trap" but when things are right they work well. My Cutlass wagon with the 305 engine got near 20 mpg on a trip and would climb a hill in the Catskills with a full load.
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